The present invention relates generally to roller chains used in packaging and conveying machinery, and more particularly to an improved device for mounting attachment members or parts to lugs or tabs provided on the roller chain. The invention has particular application in endless chain conveying or packaging machines, but is not limited to such machines.
The use of endless roller chains in machines for packaging or conveying articles is well known. The roller chain links may serve various functions, including separating conveyed items into groups, moving conveyed items, loading or pushing grouped items into cartons, etc. To carry out these various functions, the roller chains frequently require mounting of working xe2x80x9cattachmentxe2x80x9d members, such as flight bars, directly onto the roller chain links. With a certain type of commercially available roller chain, metal mounting tabs or xe2x80x9clugsxe2x80x9d are provided on the roller link plates or pin link plates. An attachment member is mounted directly onto the metal tabs.
With conventional systems, the attachment member is connected with a threaded fastener to the metal tab or to a metal backing plate. This is particularly the case if a plastic attachment member is to be attached to the roller chain. However, when chains are to be replaced, the removal of threaded mounting parts is time consuming. Also, the attachment member is occasionally exposed to relatively great stress, particularly if a jam occurs in the machine. If the attachment member is bolted or welded to the link tab, substantial damage may occur to the link or the roller chain. If this happens, the chain must be taken apart and the damaged links removed, thereby requiring a substantial amount of time and labor.
The present invention relates to an improved device for mounting any manner of attachment member to conventional roller chains that overcomes many of the disadvantages of conventional devices.
Objects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention.
The present invention relates to an improved attachment member for attaching in a snap-fit manner to a tab or lug of a roller chain link plate. The attachment member may be any type of conventional flight bar, lug, etc. The roller chains are conventional devices having alternating roller links and pin links. The roller links include opposite roller link plates and the pin links include opposite link plates. The metal tabs are formed integral with either or both of the roller link plates or pin link plates. The tabs may extend generally perpendicular from their respective link plates, or may lie in the same vertical plane as the link plates. With conventional roller chains, these metal tabs are typically provided with at least one hole defined therethrough. Wider tabs may include two holes. These holes have conventionally served for mounting attachment members with threaded fasteners or with a fastener extending therethrough into a metal backing plate.
The attachment member according to the invention includes a body member having a configuration for carrying out a desired roller chain operation upon attachment of the body member to the roller chain. It should thus be appreciated that the body member is not limited to any particular type of shape or configuration. The body member includes a bottom end having a cavity defined therein. This cavity has dimensions corresponding essentially to those of a tab carried by a roller chain link plate (roller link plate or pin link plate). In this manner, the body member is slidable with a relatively tight or snug fit onto the tab.
The body member cavity is defined by a back wall, sides, and a front wall, and further includes a protuberance that extends from either of the back wall or front wall into the cavity towards the opposite wall. This protuberance has a shape so as to fit into a hole defined in the tab upon the body member being slid onto the tab. In this manner, the body member xe2x80x9csnap-fitsxe2x80x9d onto the tab to securely attach the attachment member to the roller chain.
The body member may be formed of a plastic material so as to minimize inertia forces which tend to limit machine speeds and increase wear of components.
The back wall of the cavity may also include a resilient tab defined between two longitudinal slits. The protuberance may be provided on this resilient tab. In this manner, the resilient tab adds to the snap-fit action of the attaching device upon the body member being slid onto the tab of the roller chain link plate.
It should be appreciated that the longitudinal slits are not necessary for operation of the device. The body member may be formed of a material having enough inherent resiliency to allow the body member to be easily slid onto the roller chain tab member without the aid of a slit.
The front wall may further comprise an opening defined therethrough into the cavity. This opening is aligned opposite from the protuberance so that a visual verification may be made that the attachment member has been properly secured to the roller chain. The opening may also provide access for a tool to aid in disengaging the attachment member from the roller chain.
The invention also relates to a roller chain assembly that includes a conventional roller chain and the attachment member as described herein.
The invention will be described in greater detail below through use of the appended figures.